(a): case 1, the MseI and ApeKI recognition sites (in red boxes) have mutations. (b): case 2, the tester contains enough bases that do not match the driver. (c): case 3, the sequence is partially absent in the tester or driver (or completely absent in the driver). Fragments of Bgt063, Bgh017, and Bgh009 were cloned and sequenced after R-PCR reactions. *: Identical.